第18讲 Camera Java Framework AIDL概述 - Android Camera Native Framework

本讲是Android Camera Native Framework专题的第18讲，我们介绍Camera Java Framework AIDL概述。

更多资源：

资源	描述
在线课程	极客笔记在线课程
知识星球	星球名称：深入浅出Android Camera 星球ID: 17296815
Wechat	极客笔记圈

Camera Java Framework AIDL文件路径

路径：/frameworks/av/camera/aidl/android/hardware/

Android 13 ICameraService.aidl代码如下:

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.hardware;

import android.hardware.ICamera;
import android.hardware.ICameraClient;
import android.hardware.camera2.ICameraDeviceUser;
import android.hardware.camera2.ICameraDeviceCallbacks;
import android.hardware.camera2.ICameraInjectionCallback;
import android.hardware.camera2.ICameraInjectionSession;
import android.hardware.camera2.params.VendorTagDescriptor;
import android.hardware.camera2.params.VendorTagDescriptorCache;
import android.hardware.camera2.utils.ConcurrentCameraIdCombination;
import android.hardware.camera2.utils.CameraIdAndSessionConfiguration;
import android.hardware.camera2.impl.CameraMetadataNative;
import android.hardware.ICameraServiceListener;
import android.hardware.CameraInfo;
import android.hardware.CameraStatus;

/**
 * Binder interface for the native camera service running in mediaserver.
 *
 * @hide
 */
interface ICameraService
{
    /**
     * All camera service and device Binder calls may return a
     * ServiceSpecificException with the following error codes
     */
    const int ERROR_PERMISSION_DENIED = 1;
    const int ERROR_ALREADY_EXISTS = 2;
    const int ERROR_ILLEGAL_ARGUMENT = 3;
    const int ERROR_DISCONNECTED = 4;
    const int ERROR_TIMED_OUT = 5;
    const int ERROR_DISABLED = 6;
    const int ERROR_CAMERA_IN_USE = 7;
    const int ERROR_MAX_CAMERAS_IN_USE = 8;
    const int ERROR_DEPRECATED_HAL = 9;
    const int ERROR_INVALID_OPERATION = 10;

    /**
     * Types for getNumberOfCameras
     */
    const int CAMERA_TYPE_BACKWARD_COMPATIBLE = 0;
    const int CAMERA_TYPE_ALL = 1;

    /**
     * Return the number of camera devices available in the system
     */
    int getNumberOfCameras(int type);

    /**
     * Fetch basic camera information for a camera device
     */
    CameraInfo getCameraInfo(int cameraId);

    /**
     * Default UID/PID values for non-privileged callers of
     * connect() and connectDevice()
     */
    const int USE_CALLING_UID = -1;
    const int USE_CALLING_PID = -1;

    /**
     * Open a camera device through the old camera API
     */
    ICamera connect(ICameraClient client,
            int cameraId,
            String opPackageName,
            int clientUid, int clientPid,
            int targetSdkVersion);

    /**
     * Open a camera device through the new camera API
     * Only supported for device HAL versions >= 3.2
     */
    ICameraDeviceUser connectDevice(ICameraDeviceCallbacks callbacks,
            String cameraId,
            String opPackageName,
            @nullable String featureId,
            int clientUid, int oomScoreOffset,
            int targetSdkVersion);

    /**
     * Add listener for changes to camera device and flashlight state.
     *
     * Also returns the set of currently-known camera IDs and state of each device.
     * Adding a listener will trigger the torch status listener to fire for all
     * devices that have a flash unit.
     */
    CameraStatus[] addListener(ICameraServiceListener listener);

    /**
     * Get a list of combinations of camera ids which support concurrent streaming.
     *
     */
    ConcurrentCameraIdCombination[] getConcurrentCameraIds();

    /**
      * Check whether a particular set of session configurations are concurrently supported by the
      * corresponding camera ids.
      *
      * @param sessions the set of camera id and session configuration pairs to be queried.
      * @param targetSdkVersion the target sdk level of the application calling this function.
      * @return true  - the set of concurrent camera id and stream combinations is supported.
      *         false - the set of concurrent camera id and stream combinations is not supported
      *                 OR the method was called with a set of camera ids not returned by
      *                 getConcurrentCameraIds().
      */
    boolean isConcurrentSessionConfigurationSupported(
            in CameraIdAndSessionConfiguration[] sessions,
            int targetSdkVersion);

    /**
     * Remove listener for changes to camera device and flashlight state.
     */
    void removeListener(ICameraServiceListener listener);

    /**
     * Read the static camera metadata for a camera device.
     * Only supported for device HAL versions >= 3.2
     */
    CameraMetadataNative getCameraCharacteristics(String cameraId, int targetSdkVersion);

    /**
     * Read in the vendor tag descriptors from the camera module HAL.
     * Intended to be used by the native code of CameraMetadataNative to correctly
     * interpret camera metadata with vendor tags.
     */
    VendorTagDescriptor getCameraVendorTagDescriptor();

    /**
     * Retrieve the vendor tag descriptor cache which can have multiple vendor
     * providers.
     * Intended to be used by the native code of CameraMetadataNative to correctly
     * interpret camera metadata with vendor tags.
     */
    VendorTagDescriptorCache getCameraVendorTagCache();

    /**
     * Read the legacy camera1 parameters into a String
     */
    String getLegacyParameters(int cameraId);

    /**
     * apiVersion constants for supportsCameraApi
     */
    const int API_VERSION_1 = 1;
    const int API_VERSION_2 = 2;

    // Determines if a particular API version is supported directly for a cameraId.
    boolean supportsCameraApi(String cameraId, int apiVersion);
    // Determines if a cameraId is a hidden physical camera of a logical multi-camera.
    boolean isHiddenPhysicalCamera(String cameraId);
    // Inject the external camera to replace the internal camera session.
    ICameraInjectionSession injectCamera(String packageName, String internalCamId,
            String externalCamId, in ICameraInjectionCallback CameraInjectionCallback);

    void setTorchMode(String cameraId, boolean enabled, IBinder clientBinder);

    // Change the brightness level of the flash unit associated with cameraId to strengthLevel.
    // If the torch is in OFF state and strengthLevel > 0 then the torch will also be turned ON.
    void turnOnTorchWithStrengthLevel(String cameraId, int strengthLevel, IBinder clientBinder);

    // Get the brightness level of the flash unit associated with cameraId.
    int getTorchStrengthLevel(String cameraId);

    /**
     * Notify the camera service of a system event.  Should only be called from system_server.
     *
     * Callers require the android.permission.CAMERA_SEND_SYSTEM_EVENTS permission.
     */
    const int EVENT_NONE = 0;
    const int EVENT_USER_SWITCHED = 1; // The argument is the set of new foreground user IDs.
    const int EVENT_USB_DEVICE_ATTACHED = 2; // The argument is the deviceId and vendorId
    const int EVENT_USB_DEVICE_DETACHED = 3; // The argument is the deviceId and vendorId
    oneway void notifySystemEvent(int eventId, in int[] args);

    /**
     * Notify the camera service of a display configuration change.
     *
     * Callers require the android.permission.CAMERA_SEND_SYSTEM_EVENTS permission.
     */
    oneway void notifyDisplayConfigurationChange();

    /**
     * Notify the camera service of a device physical status change. May only be called from
     * a privileged process.
     *
     * newState is a bitfield consisting of DEVICE_STATE_* values combined together. Valid state
     * combinations are device-specific. At device startup, the camera service will assume the device
     * state is NORMAL until otherwise notified.
     *
     * Callers require the android.permission.CAMERA_SEND_SYSTEM_EVENTS permission.
     */
    oneway void notifyDeviceStateChange(long newState);

    // Bitfield constants for notifyDeviceStateChange
    // All bits >= 32 are for custom vendor states
    // Written as ints since AIDL does not support long constants.
    const int DEVICE_STATE_NORMAL = 0;
    const int DEVICE_STATE_BACK_COVERED = 1;
    const int DEVICE_STATE_FRONT_COVERED = 2;
    const int DEVICE_STATE_FOLDED = 4;
    const int DEVICE_STATE_LAST_FRAMEWORK_BIT = 0x80000000; // 1 << 31;

}

Camera Java Framework AIDL产生的库/文件

AIDL产生的Java源文件：

• out\soong\.intermediates\frameworks\base\framework-minus-apex\android_common\gen\aidl\ aidl36.srcjar

AIDL产生的C++源文件：

• out\soong\.intermediates\frameworks\av\camera\libcamera_client\android_arm64_armv8-a_cortex-a55_shared_cfi\gen\aidl\android\hardware

Camera Java Framework AIDL核心类

Class	Description
ICameraService.aidl	Cameraserver进程对外提供的入口接口
ICameraServiceListener.aidl	ICameraService的回调类，通知CameraService相关状态
ICameraDeviceUser.aidl	用于操作某一颗Camera Device
ICameraDeviceCallbacks.aidl	Camera Device的回调类

Camera Java Framework AIDL核心类之间的调用关系如下图所示：